Terephthalate polyester resins are thermoplastic polymers that are widely used in the plastics industry. Terephthalate polyesters resins are used in the manufacturing of films, bottles, plastic containers of all kinds, carpets and carpet products, fibers, fabrics, all kinds of textile materials, strapping, and the like.
A major problem with reprocessing terephthalate polyester resins is that when heated in the presence of moisture, polyesters may partially hydrolyze to polymer of severely reduced molecular weight. Polyesters must therefore be very dry during processing, typically containing less than 50 ppm moisture, in order to prevent unacceptable levels of hydrolysis. In view of this challenge, conventional reprocessing of the polyesters represents a technological and economic challenge.
Furthermore, with the growing use of terephthalate polyester products, major waste disposal problems and expenses have been encountered by both the manufacturers and the consumers. For example, the carpet industry is one of the industries that are facing a growing challenge of disposing of polyester based products. Unlike two common types of nylon (6,6 and 6), which can be recycled back into a new carpet or reused in other applications, polyester based carpet currently has no economically viable afterlife. Whereas nylon (6,6 and 6), for example, can technically chemically processed and then re-extruded into useful articles. The same cannot be said for the polyester which loses its tensile strength after its initial use as a carpet. The large quantities of the sold polyester based carpets creates availability of more than 100 MM lbs/yr of post-consumer carpet with no more economical outlet than use as a boiler fuel.
One of the possible ways for recycling polyester face fiber reclaimed carpet products can be producing other phthalate esters, and particularly terephthalate esters. Terephthalate esters are mainly used as plasticizers added to plastic to increase its flexibility, transparency, durability, and longevity. Terephthalate esters can be used to soften various polymers for example polyvinyl chloride (PVC). Due to the safety concerns, previously popular lower molecular weight phthalates are being replaced by high-molecular-weight terephthalates, or those with more than 6 carbons in their backbone, which gives them, increased permanency and durability, and decreased toxicity. Additionally, terephthalate esters are fortuitously less biologically active (i.e. estrogen mimicking) than phthalate esters. A common manufacturing process for terephthalate esters is based on the transesterification reaction. Unfortunately, the conventional process is slow, making the process economically undesirable.
Accordingly, there is a need for an efficient process for producing a terephthalate ester. Still further, there is a need for a recycling process for reclaimed carpet materials comprising polyester components. It would be further desirable to have a process for producing a terephthalate ester from a reclaimed carpet material. And even further, it would be desirable to have a process for producing a diol from a reclaimed carpet material. These needs and other needs are at least partially satisfied by the present invention.